Bryce, Murray D.
The McGraw-Hill Book Company, 1960
Buku Teks
Bruton, Henry J
Buku Teks
Mennes, L.B.M., author
North-Holland Publishing, 1969
Buku Teks
Adelman, Irma, author
Stanford University Press, 1961
Buku Teks
Hirschman, Albert O.
New York, N.Y. University Press, 1958
Buku Teks